Carbon black filled rubber compositions in a tire building plant are desirably identified so that a preselected tread compound is applied to each tire type. Tread identification is also used to confirm at specified time intervals that the correct tread compound is being applied to the appropriate tire type. If the identification is applied to the outside of the tread and if the identification is designed to remain during tire curing (vulcanization), then the tire tread composition can be identified by visual inspection.
Tire manufacturers use inks (pigment, binder,and solvent) to identify the one or more tread compositions within a tire building plant. Often the ink is applied longitudinally along the hot tread after it is shaped by molding or extruding. Subsequently the tread is cooled (e.g. with a water spray) and put into inventory or cut to length and assembled into tires. The solvent in the ink is unfortunately volatilized into the work place unless collected by expensive solvent recovery systems. Solvent based inks have been particularly successful due to their fast drying times, resistance to water spray, durability, good substrate wetting, good adhesion to the substrate, and the visibility of the resulting coating. It is also important that the color does not transfer to the mold during the curing step.